1. Technical Field
The disclosure relates to coating technology and, particularly, to a coating apparatus with a clamping device.
2. Description of Related Art
Infrared (IR) cut-off filters are configured to reflect or block mid-infrared wavelengths while passing visible light, and are generally equipped in cameras as key elements thereof. The IR cut-off filters are manufactured by forming IR cut-off films on substrates by applying an evaporation process, or another coating method such as sputtering process.
Generally, when coating an IR cut-off film on a surface of the substrate using for example, an evaporation process, a clamping device may first be provided to clamp the substrates. And then a functional material can be evaporated on the surface of the substrates to form the optical film. A typical clamping device generally includes two clamping jaws. In use, the two clamping jaws abut against two peripheral sides of the substrate. However, the evaporation process is generally applied with a high temperature above about 200° C., and the substrate tends to get distorted in such a high temperature. In such case, the IR cut-off film may not be coated on the substrate uniformly, and thus optical performance of the Infrared cut-off filter may be diminished in certain applications.
Therefore, what is needed, is a coating apparatus with a clamping device, which can overcome the above shortcomings.